Present invention relates to an X-ray detector with a multi-channel type ionization chamber having a plurality of high voltage plate electrodes supplied with a high voltage and a plurality of signal plate electrodes for taking out a signal corresponding to an amount of detected X-rays, the high voltage plate electrodes and the signal plate electrodes being arranged in parallel to and alternating with each other.
The high voltage plate electrodes are connected in parallel to an electrically conductive rubber member which is disposed in an arranging direction of the plate electrodes and is supplied with a high voltage, and at the same time, the high voltage plate electrodes are fixedly supported by disposing the conductive rubber member between the high voltage plate electrodes and an electrically insulating support member.
Such electrical connection by use of a conductive rubber member makes it easy to assemble an X-ray detector having a fine construction, and an example of such a detector is described in Japanese Patent Laid-open No. 58-168981 (1983) .
However, in the X-ray detector having a construction as described above, a voltage drop in the high voltage plate electrode arises in relation to the distance from the end of the conductive rubber member which is connected to the high voltage source to a position at which the conductive rubber member is connected to the respective high voltage plate electrodes, because the conductive rubber has a significantly large resistance.
Such a voltage drop causes generation of voltage differences between the high voltages applied to the respective plate electrodes and makes it difficult to take out a signal which accurately reflects the amount of the X-rays which should be detected.
It is possible to decrease the resistance of the conductive rubber member; however, this creates the problem that the process for producing the conductive rubber member becomes complex and the elasticity of the rubber decreases so significantly that it becomes impossible to firmly support the plate electrodes on the insulating support member.